U.S. Brig. Gen. Terence Hildner died in Kabul of apparent natural causes , officials said , making him the highest ranking officer to die in Afghanistan .

He was 49 .

Hildner , who was commander of the 13th Expeditionary Sustainment Command , Fort Hood , Texas , was in Afghanistan to support the NATO training mission .

`` The unfortunate and untimely death of Brigadier General Hildner was a shock to our unit and Families , '' Col. Knowles Atchison , 13th ESC rear commander , said in a statement posted on the Fort Hood website . `` Both forward deployed elements and we at home station are deeply saddened by this loss . We will all pull together through this difficult period and care for one another . ''

The circumstances surrounding his death are under investigation , the statement said .

Hildner graduated from the University of Notre Dame in 1984 and attended the U.S. Army Command and General Staff College in 1997 . A Connecticut native , he listed his home in Fairfax , Virginia .

In 2003 , Hildner assumed command of the 13th Corps Support Command 's Special Troops Battalion at Fort Hood . That battalion conducted two operational deployments during his years in command -- the first in support of Operation Iraqi Freedom , the second in the wake of Hurricane Katrina .

Previously , Hildner served in Iraq during Operation Desert Storm and participated in the last U.S. patrol along the East-West German border before its reunification .

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Terence Hildner , 49 , died of `` apparent natural causes ''

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He was commander of the 13th Expeditionary Sustainment Command

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Hildner was in Afghanistan to support the NATO training mission

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His death is under investigation